Plant and soil responses to salvaged marsh surface and organic matter amendments at a created wetland in central Pennsylvania

To evaluate the efficiency of different methods of wetland plant establishment and different soil amendments, 16 experimental plots in 4 treatment groups were established at a 6-ha created palustrine wetland in Tipton, PA. Response of vegetation, soil, and hydrology were evaluated. The first objective of the study was to determine if salvaged marsh surface (SMS) from a donor wetland can be used to effectivly vegetate experimental plots. The results were compared with control plots. In addition, the possibility of using a non-toxic organic waste (leaf litter compost) as a soil amendment to created wetland projects was examined. Lurid sedge (Carex lurida) tubers were hand-planted in the leaf litter plots and in the existing mineral soils of the remaining experimental plots. SMS plots had significantly greater plant species richness, total vegetative coverage, and diversity than control plots. SMS plots contained more hydrophytic vegetation and less undesirable vegetation than control plots. SMS added significant amounts of organic matter and soil nutrients (e.g., nitrogen) to the soils in treated plots. Survivorship of hand-planted Carex was greater (79.0 ± 5.0 % for both July and August 1992) on plots treated with leaf litter compost than on plots with existing mineral soils (45.0 ± 20.0% in July and 38.0 ± 20.0 % in August 1992). Organic matter, pH, total N, and NO₃ levels were all significantly greater on leaf litter plots than on hand-planted plots after the 1991 growing season. At the end of the 1992 growing season, organic matter, pH, NO₃, and NH₄ levels were significantly greater on leaf litter plots than on hand-planted plots. The results of the study suggest that SMS can be used as a method to successfully revegetate created wetlands. Also, the addition of leaf litter compost to experimental plots helped to retain soil moisture and provide nutrients that enhanced survivorship of hand-planted Carex.